As the premier offering from an automotive brand known both for high-quality products and fuel-efficient hybrid technology, the 2014 Lexus LS 600h L leaves us scratching our heads. On one hand, the LS 600h L is the flagship of flagships, the Lexus LS model with the most features, the most power, and thanks to its hybrid powertrain, the best fuel economy.

On the other hand, this full-size hybrid luxury sedan is extremely expensive, and its EPA-rated fuel economy is only 1 mile per gallon better than its non-hybrid counterpart, the Lexus LS 460 (which is reviewed separately). To put that in sharper focus, if you drive 15,000 miles a year and pay $4 a gallon for gas, it would take you 156 years to recover the extra upfront cost of the hybrid Lexus LS. To add insult to injury, the LS 600h L is not any quicker than the standard LS despite having a larger 5.0-liter V8 engine plus an electric motor working on its behalf. The problem is not a lack of horsepower; rather, it's the Lexus LS 600h L's excessive weight. With the burden of batteries and various other hybrid components, it outweighs many SUVs.

Granted, there's more to the 2014 Lexus LS 600h L than just the numbers. Occupants will enjoy almost decadent levels of opulence in this massive hybrid luxury sedan, particularly if you spring for the Executive package that turns the right rear seat into a throne worthy of any royal court. Interior materials are world-class, and the quantity and sophistication of its technological features are easily on par with the best European luxury sedans. Then again, you can get all of these amenities in the long-wheelbase LS 460 L, too.

If you're looking for a fuel-efficient drivetrain in a high-end luxury sedan, there are several compelling alternatives, including the Porsche Panamera S E-Hybrid (which is a plug-in hybrid), the BMW ActiveHybrid 7 and the diesel-powered Audi A8 L TDI, all of which have far superior mpg ratings. A slightly more offbeat option is the all-electric Tesla Model S, should your lifestyle accommodate an electric vehicle and the numerous compromises that EV ownership entails.

Of course, all of these cars come with lofty price tags of their own. But if you're really serious about buying an elite luxury sedan that consumes less fuel, they'll take you farther toward that objective than the 2014 Lexus LS 600h L.

The 2014 Lexus LS 600h L is a four- or five-passenger luxury sedan that is offered in a single, very well-appointed trim level. Standard features include 19-inch alloy wheels, an air suspension (with adjustable shock absorber damping), a sunroof, adaptive LED headlights, running lights, foglights, automatic high beams, headlamp washers, heated mirrors, front and rear parking sensors, a power trunk lid, keyless ignition/entry, cruise control, auto-dimming mirrors and a blind-spot monitoring system with cross-traffic alerts.

Inside you'll also get four-zone automatic climate control; ambient interior lighting; leather upholstery; a 12-way power-adjustable driver seat (10-way front passenger seat); heated and ventilated front and rear seats with memory functions; power-reclining rear seats with massage functions; a heated leather-wrapped steering wheel with power tilt-and-telescoping adjustments; wood interior trim; power rear sunshades and a rear-seat refrigerator.

Standard electronics include a navigation system with a 12.3-inch display, a rearview camera, Bluetooth phone and audio connectivity, Lexus Safety Connect emergency communications, the Lexus Enform suite of smartphone-integrated apps and the Siri Eyes Free interface (which provides additional voice control functionality for newer iPhones). The standard 19-speaker Mark Levinson surround-sound system comes with a six-disc CD changer, HD and satellite radio, USB/iPod integration and rear-seat audio controls.

Optionally you can add the Executive package, which reduces seating capacity to four but adds infrared cabin temperature sensors, additional leather interior trim, a rear-seat DVD/Blu-ray entertainment system, a right rear seat with a power ottoman and additional massage functions and added rear airbags. Also available are two adaptive cruise control systems, one paired with a pre-collision system and one that adds a more advanced forward collision avoidance system with a driver attention monitor along with a lane departure warning/prevention system.

Powering the 2014 Lexus LS 600h L is a hybrid powertrain comprising a 5.0-liter V8 engine that produces 389 horsepower and 385 pound-feet of torque mated to two electric motor/generators; one acts as a primary generator and engine starter while the other drives the rear wheels and produces power through regenerative braking. Combined, the entire system has an output of 438 hp. All of this power is routed to an all-wheel-drive system via a continuously variable transmission (CVT).

In Edmunds testing, the LS 600h L reached 60 mph in 6.4 seconds, a slow time for a luxury sedan with this much power on tap. Fuel economy is barely better than the regular LS 460, as the EPA rates the hybrid LS at 20 mpg combined (19 mpg city/23 mpg highway).

Standard safety features on the 2014 Lexus LS 600h L include antilock disc brakes, stability and traction control, front and rear side airbags, side curtain airbags, driver knee airbags, a blind-spot monitoring system with cross-traffic alerts, front and rear parking sensors, adaptive headlights, automatic high beams, a rearview camera and Lexus' Safety Connect emergency telematics.

The optional adaptive cruise control system includes a pre-collision system that preps various vehicle systems when it detects a possible collision. Sold as a separate option is the more sophisticated Advanced Pre-Collision system, which includes a driver attention monitor and can automatically initiate braking to help avert forward collisions. This option also includes a lane departure warning and prevention system.

In Edmunds testing, an LS 600h L stopped from 60 mph in 126 feet, which is a long braking distance for an elite luxury sedan but understandable given that this car weighs over 5,400 pounds (more than many SUVs). The Insurance Institute for Highway Safety gave the LS the highest possible rating of "Good" in the moderate-overlap frontal-offset crash test, and the sedan's seat/head restraint design also rates "Good" for whiplash protection in rear impacts.

Initial propulsion from a stop is supplied by the electric motors, resulting in eerily silent acceleration in the 2014 Lexus LS 600h L. Even when the 5.0-liter V8 engine starts up, it's hard-pressed to grab center stage, as the LS hybrid's meticulously soundproofed cabin remains blissfully quiet at highway speeds, regardless of the road surface.

The LS 600h L offers four driver-selectable settings for its suspension, varying between Comfort and Sport+. In Comfort mode, the ride is quite soft, while the sportier modes attempt to provide more control for going around turns. However, this is an exceptionally heavy car, and if you start making big demands, you'll find that the hybrid LS responds with the haste of a cruise ship. The steering, at least, is precise and light on effort, making it pretty easy to park.

As the flagship of the Lexus flagship line, the LS 600h L offers abundant luxury. The standard semi-aniline leather on the seats is the automaker's best, and the simulated suede headliner looks rich and is soft to the touch. The optional Executive package brings even more leather into the cabin, while offering the right rear passenger his own ottoman. Rich, grain-matched wood trim is also plentiful, giving the interior a traditional luxury car feel. Particularly striking is the available black interior treatment with bamboo wood trim.

The Remote Touch electronics interface is a part of the car's technology array. It's a mouselike device that allows the user to navigate among a variety of function icons on a horizontally oriented, 12.3-inch display at the top of the dashboard. However useful Remote Touch is for integrating basic tasks and smartphone applications, it ultimately draws too much attention away from the road. Cursor control with the Remote Touch controller is wobbly and imprecise, making audio and navigation selections difficult when you're on the move. Other companies use different solutions for their technology interface systems, and in particular, we prefer BMW's iDrive. If you're planning to buy an LS 600h L, Remote Touch should be tested out thoroughly at a dealership.

Cargo space is at a premium in the hybrid LS. The separate rear climate control system, onboard refrigerator and hybrid system components drop trunk capacity to a mere 13 cubic feet, compared to the standard LS 460's generous 18 cubes.